Jim,
Just got back from the hangar. It looks like mine is between 7.5 and 8.0 inches from the front of the gear leg where it exits the bottom of the cowl to the forward most part of the slot. I have the FairingsEtc intersection fairing that I cut and glassed so it extends forward sufficient to cover the extended slot.
Please note that I have the James cowl which is slightly longer than Vans stock unit--don't think this would matter but .....??? I arrived at this dimension by cutting forward a little at a time until I was satisfied that I had the shortest slot that allowed bottom cowl removal.
Regardless, as has been mentioned, you need to protect the 3 blade composite prop when you remove the bottom cowl.
Hope this helps!
Cheers,
db